1. Field of the Invention
The present invention is directed to a throughput control system for an agricultural combine wherein the actual hydraulic pressure of the variable torque sensing drive is used to control the harvesting speed of the combine.
2. Description of the Prior Art
Agricultural combines are large machines that harvest, thresh, separate and clean an agricultural crop. The resulting clean grain is stored in a grain tank located on the combine. The clean grain can then be transported from the grain tank to a truck, grain cart or other receiving bin by an unloading auger.
A harvesting assembly located at the front of the combine harvests the crop. The harvested crop is directed to a feederhouse for delivering the harvested crop material to a threshing assembly. The threshing assembly may either be a conventional transverse threshing cylinder and concave, or a rotary threshing assembly. The rotary threshing assembly may be arranged axially or transversely. The forward harvesting speed of the combine controls the amount of harvested crop material ingested by the threshing assembly. A variable diameter torque sensing drive typically drives the threshing assemblies. Such a drive is currently used on John Deere 50 Series combines manufactured by the assignee of this patent application.
Various throughput control systems have been proposed to facilitate combine efficiency. Some of these systems sense grain loss using grain loss monitors. Other systems sense crop material throughput and try to maintain a relatively constant throughput of crop material.
It is an object of the present invention to provide a simple and effective throughput control system for an agricultural combine.
An agricultural combine having a supporting structure is driven by ground engaging wheels at a harvesting speed by a propulsion assembly. The combine is also provided with a threshing assembly that is driven by a variable torque sensing drive. The variable torque sensing drive is manipulated by pressurized hydraulic fluid. A hydraulic sensor in hydraulic communication with the variable torque sensing drive provides an actual hydraulic pressure signal that is directed to an electronic controller. An operator control in the operator""s cab of the combine provides a loss rate signal that is also directed to the electronic controller. The electronic controller converts the loss rate signal into a desired hydraulic pressure signal. The electronic controller regulates the forward speed (harvesting speed) of the combine so that the desired hydraulic pressure signal is equal to the actual pressure signal.
A further refinement to the throughput control system is the use of a moisture sensor on the feederhouse to measure the moisture content of harvested crop material before it enters the threshing assembly. The moisture signal is directed to the electronic controller and can be used to modify the desired hydraulic pressure signal or the actual pressure signal, to thereby modify the harvesting speed of the combine.
Cumulatively or alternatively the moisture signal can be used to immediately change the speed of the combine if the moisture signal falls outside certain preset limits or the moisture is dramatically changed from previous moisture readings. For example, if the combine is entering a green weedy patch in the field, the moisture sensor would signal high moisture crop material, the controller in turn would immediately slow down the combine to better accommodate this heavy load. Similarly, as the combine passes out of this weedy patch the controller would automatically speed up the combine as the combine enters more normal crop conditions. As stated above, the moisture signal can be used to simply modify one of the hydraulic pressure signals and/or be used against moisture set points to override the normal throughput control using the actual hydraulic pressure of the variable torque sensing drive.